The present invention relates to the field of electronic imaging devices, and more particularly to a method and apparatus for precision mounting of an imaging device such as a liquid crystal display (xe2x80x9cLCDxe2x80x9d) imaging device. The predominant current usage of the inventive precision surface mount is in the surface mounting of reflective imaging devices in a multi channel projection system, wherein it is particularly important to maintain a precise relationship between a reflective surface of the LCD and a mounting surface.
Projection type imaging devices commonly use micro LCD imagers. Since the pixel size and spacing on these are so small, they must be precisely placed in relation to surface whereon they are mounted. A typical required gap between the imager and an adjacent surface must be between 0.000 inch and 0.006 inch. Since the cumulative tolerances of the stack-up height of the components on the imager can typically be much larger than the allowable 0.006 inch tolerance, a pre-determined frame thickness cannot be designed to consistently produce imagers that have frames attached and which meet this requirement. Moreover, it is important to maintain the flatness of the imaging device in order to maintain uniformity of the focal plane and to enhance convergence with other such devices in the system.
To the inventors"" knowledge, no prior method or apparatus has existed which will consistently result in the precise placement of micro LCD imaging devices necessary for application in high resolution multi channel image projection units. All previous methods have either been insufficiently precise and/or have not produced a consistently acceptable result.
Accordingly, it is an object of the present invention to provide a method and apparatus for mounting display devices which will result in a video projection engine that will provide sub-pixel accuracy over an entire image range.
It is still another object of the present invention to provide a method and apparatus for mounting display devices which will consistently and reliably result in imagers accurately placed in relation to a mounting surface.
It is yet another object of the present invention to provide a method and apparatus for mounting display devices which is inexpensive to implement, both in time and materials.
It is still another object of the present invention to provide a method and apparatus for mounting display devices which can precisely position the display devices in relation to a mounting surface.
Briefly, an embodiment of the present invention employs an attachment chuck wherein the a display device is held in place by vacuum. A high viscosity and thixotropic ultra violet (xe2x80x9cUVxe2x80x9d) cure adhesive is dispensed onto the imager front side, whereon the frame will be adhered. A spacer, the thickness of the spacing required is placed on the chuck, along with a frame onto which the display device is to be mounted. The display device is then placed in the chuck and the vacuum applied, an optional spring loaded retainer is also pivoted into position to hold the display device against the spacer. A UV light source is then applied from all edges, normal to the exposed surface of the adhesive, until the adhesive is cured. the vacuum is then turned off, the spring loaded retainer moved out of position, and the display device and frame assembly is removed.
An advantage of the present invention is that a display device can be consistently and accurately affixed in relation to a mounting surface.
Another advantage of the present invention is that a display device can be mounted without a great labor expense in an assembly environment.
Yet another advantage of the present invention is that a display device can be mounted without a great expense in materials.
Still another advantage of the present invention is that a multi channel imaging engine can be produced which has sub pixel accuracy and precise focus.
These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of modes of carrying out the invention, and the industrial applicability thereof, as described herein and as illustrated in the several figures of the drawing. The objects and advantages listed are not an exhaustive list of all possible advantages of the invention. Moreover, it will be possible to practice the invention even where one or more of the intended objects and/or advantages might be absent or not required in the application.